Internal combustion engines may operate at a level of power output far below that which it can produce. Such a partial load operation often causes the engine to operate at a level of thermal efficiency far below that which the engine can achieve. As a result, the fuel efficiency is compromised. Thus, engines may not be operated close to the maximum operating efficiency during certain operating conditions.
The Inventors have recognized the aforementioned problems and developed a method for operating an internal combustion engine. The method includes during a first operating condition, operating two primary cylinders coupled to a crankshaft and two secondary cylinders coupled to the crankshaft to perform combustion, the two primary and secondary cylinders arranged in an inline configuration, the two primary cylinder adjacent to one another, the two secondary cylinders adjacent to one another, and the secondary cylinders positioned 175°-185° out of phase relative to the two primary cylinders with regard to a crank angle. The method further includes during a second operating condition, selectively deactivating the two secondary cylinders to perform combustion in only the two primary cylinders. In this way, cylinders in the engine may be deactivated during certain operating conditions to enable the power output of the engine to better match load demands in the vehicle, if desired. As a result, engine operation may be improved. Moreover, disabling the cylinders with this type of cylinder arrangement enables exhaust gas interference in the exhaust system to be substantially eliminated, thereby improving combustion efficiency. Additionally, deactivating the cylinders in this way may enable exhaust treatment devices in the exhaust downstream of the cylinders to reach a desirable operating temperature more quickly due to the higher temperature combustion performed in the active cylinders. As a result, engine emissions can be reduced.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.